The present invention relates to an ink-jet head used for an ink-jet printer and the manufacturing method for the same.
Conventional technology utilizes, the piezoelectric effects of a piezoelectric element as an actuating force for ink-emission by an ink-jet printer. For example, there is described in Japanese Patent Publication No. 4-48622, an ink-jet head system in which an electrode layer is formed inside a fine groove formed on a piezoelectric substrate and further aforesaid electrode layer is covered with an insulating layer for forming an ink path.
The purpose of aforesaid insulating layer is to minimize deformation of the ink and to protect the electrode. It is required that the aforesaid insulating layer be inactive to the ink and the electrode and that it has an affinity to the ink so that feeding of the ink into the flowing path is smooth. As the insulating layer having aforesaid properties, a resin layer composed of a poly-para-xylylene (also referred as a palylene layer) is disclosed in Japanese Utility Publication Open to Public Inspection No. 5-60844 and Japanese Patent Publication Open to Public Inspection (hereinafter, referred as JP) Nos. 6-238897, 6-286150 and 7-246702. Aforesaid resin layer is formed by a CVD (Chemical, Vapor Deposition) method in which a solid di-para-xylylene dimer is used as a deposition source. Namely, a stable di-radical para-xylylene monomer which occurred due to gassification and heat decomposition of di-para-xylylene dimer is adsorbed on a substrate for polymerization reaction and thereby a layer is formed.
When an ink path is processed, ordinarily, after an electrode layer and an insulating layer are formed on a groove on a piezoelectric substrate, the other lid member is adhered thereon. Therefore, in the electrode side member on which a resin layer is applied entirely over the surface including the portion to which the adhesive layer will be applied, deterioration of the adhesive agent and adhesive force reduces the life of the head.
Because the aforesaid resin layer is lipophilic, it is necessary to surface process the resin layer to make it hydrophilic to accommodate the use of water-based ink. In aforesaid technologies, graft polymerization processing, plasma processing, coupling reaction processing, dipping processing using a chromic acid mixture solution and forming of an inorganic mill scale are disclosed. By the use of any of aforesaid conventional processing method of the ink path, the water-based ink emission performance cannot be maintained for a long time employing any of the above-mentioned processing.
The present invention was devised in view of the above-mentioned situations. An objective is to provide an ink-jet head excellent in terms of water-based ink emission performance for a long time and life thereof.
The above-mentioned objective of the present invention can be attained by a method of manufacturing an ink-jet head in which an ink chamber having at least one vibration wall having an electrode layer on a piezoelectric ceramic substrate is composed of at least two members such as a member having the above-mentioned vibration wall and a member forming a fixed wall. The aforesaid two or more members are adhered together into an integral structure to form a chamber therefore, a resin layer composed of poly-para-xylylene or its derivative is formed on an electrode layer in aforesaid chamber by means of a vapor phase polymerization.
In the above-mentioned manufacturing method, the following are preferable examples:
1. The above-mentioned resin layer is subjected to plasma processing;
2. The above-mentioned electrode layer is composed of aluminum, tantalum or titanium;
3. After the above-mentioned electrode layer is subjected to anodic oxidation processing, a resin layer composed of poly-para-xylylene or its derivative is formed.
The above-mentioned objective is attained by an ink-jet head having at least one vibration wall having an electrode layer on a piezoelectric ceramic substrate, wherein a resin layer composed of poly-para-xylylene or its derivative formed over the complete the surface of inner wall of aforesaid chamber by means of the vapor phase polymerization method.
Namely, the present inventors discovered that life and ink emission performance can be extended by shielding the ink path, including the adhesive agent used to assemble the ink-jet head, from ink with a resin layer formed by means of the CVD method after assembling the members forming the ink path. Further, it was also confirmed that the effects of the present invention can be provided more noticeably if aforesaid resin layer is subjected to plasma processing during the aforesaid forming method.